The Dinosaur Electronics FAN 50 Plus Pins is designed to replace the new Suburban and Atwood/HydroFlame Fan Control boards as well as maintain backward compatibility with the Fan 50 Plus and UIB Fan Control boards which have been available since 1994. This board can also be used to upgrade older furnaces to add the Fan Control feature. The purpose of a Fan Control Ignitor Board is to shut the fan motor off if the board fails to sense a flame after the third ignition try. This reduces the battery drain and eliminates the needless blowing of cold air. After shutting off the fan motor, this board will wait for one hour and repeat the whole sequence again before permanent shut down. This board should not be used in DuoTherm 900 series furnaces or any other furnace that has the thermostat in the ground circuit.